ERBB2 and breast cancer: Currently, traditional prognostic considerations include the patient’s age, TNM (tumor-lymph node-metastasis) stage, histological grading, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (c-erbB2 or HER2) status have been used as prognostic elements in breast cancer, but reliable and economical prognostic models are still lacking (D’Eredita’ et al., 2001).